<html>
<head>
<meta charset="utf-8">
<title>主界面</title>
</head>
<style>
    .flex-container {
    display: -webkit-flex;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    height: 100%;
    background-color: rgb(241, 231, 201);
    }
    .btn {
    background-color: transparent;
    width: 20%;
    height: 10%;
    margin: 10px;
}

    .update {
    text-align:center;
    border-radius: 10px;
    border: 3px solid #8AC007; 
    width: 100%;
    height: 100%;
    margin:10px;
    font-size: 200%;
    background-color:transparent;
    }
</style>
<body>
    <div class="flex-container">
        <div class='btn'>
            <button class="update" touchstart="update1();" onclick="update1();">第一步：启动处理</button>
        </div>
        <div class='btn'>
            <button class="update" touchstart="update2();" onclick="update2();">第二步：启动接收</button>
        </div>
        <div class='btn'>
            <button class="update" touchstart="update3();" onclick="update3();">第三步：启动显示</button>
        </div>
    </div>
</body>
<script>    
    var update1 = function(){
      var addr = window.location.host;
      window.location.href="http://"+addr+"/1/";        
    };
    var update2 = function(){
      var addr = window.location.host;
      window.location.href="http://"+addr+"/2/";        
    };
    var update3 = function(){
      var addr = window.location.host;
      window.location.href="http://"+addr+"/3/";        
    };
</script>
</html>